Linear photographic processing system



Oct. 11, 1966 s. 1.. HERSH LINEAR PHOTOGRAPHIC PROCESSING SYSTEM 2 Sheets-Sheet 1 Filed April 22, 1964 SPEED DRIVE FIG! FIGS

INVENTOR, SEYMOUR 1 HERSH.

ATTORNEY- Oct. 11, 1966 S. l... HERSH LINEAR Filed April 22, 1964 PHOTOGRAPHIC PROCESSING SYSTEM 2 Sheets-Sheet 3 INVENTOR, SEYMOUR L. HERSH.

ATTORNEY;

United States Patent 3,277,810 LINEAR PHOTOGRAPHEC PROCESSING SYSTEM Seymour L. Hersh, Freehold, N.J., assignor to the United States of America as represented by the Secretary of the Army Filed Apr. 22, 1964, Ser. No. 361,913 1 Claim. (CI. 9594) The invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment of any royalty thereon.

This invention relates to an apparatus and system for processing photographic films and printing paper and particularly to such apparatus wherein the film or other element is transported from one solution to another without substantially deviating from a continuous flat plane and without emerging from the solutions during processing.

Prior apparatus have included a complex system of directional rolls to feed film downward into successive solutions contained in processing tanks, thence upward into the atmosphere out of one solution and then down into a succeeding solution tank. This technique imposed many disadvantages such as partial exposure to the atmosphere; unnecessarily long lengths of film threaded thru the system which in turn restricted fast processing of the film. Moreover the present invention permits a substantial reduction in the size of the complete equipment.

The invention provides a series of tanks arranged in close proximity to each other or in a different construction a single tank having partitioning walls therein to provide a plurality of compartments to receive various processing solutions. The common wall between tanks are provided with narrow submerged slots thru which the film is transported from tank to tank. Special means are provided at the slots to prevent flow of solution from tank to tank.

In operating the system film is fed in a linear path thru all the tanks and enters a final compartment completely processed where it is wound upon a takeup spool.

It is a primary object of the invention to provide a compact and elficient processing apparatus for photographic materials.

A further object of the invention is to provide a photographic processing apparatus wherein a minimum length of film is immersed in processing solution.

A further object of the invention is to provide photographic processing equipment of greatly reduced size.

A further object of the invention is to provide photographic processing equipment which functions with the film completely immersed in solution throughout the multistage processing cycle.

A further object of the invention is to provide a photographic processing system in which an element to be processed may pass from one bath to another instantaneously with no exposure to the atmosphere thereby providing for precise time and temperature control throughout the cycle.

A further object of the invention is to provide a processing apparatus which is adapted to precision sensitometry.

A further object of the invention is to provide photo processing apparatus wherein accurately controlled fast processing cycles may be used whose total time is of the order of a few seconds.

Other objects and features of the invention will more fully appear from the following detailed description and will be particularly pointed out in the appended claim.

To provide a better understanding of the invention specific embodiments thereof will be described and illustrated in the accompanying drawings wherein:

FIG. 1 is a plan view of one embodiment of the invention.

FIG. 2 is a cross sectional view on line 2-2 FIG. 1.

FIG. 3 illustrates partially diagrammatically a different form of the invention.

FIG. 4 is a detail cross section on line 4-4 FIG. 2 showing a liquid sealing means through which the film passes from one tank section to another.

FIG. 5 illustrates another structure for the seal shown in FIG. 4.

FIG. 6 illustrates diagrammatically hydrostatic means to control How of liquid at the seals between tank sections.

FIG. 7 illustrates another means for controlling liquid seepage between tank sections.

FIG. 8 is a cross section on line 88 FIG. 7.

Heretofore the processing of photographically sensitive materials has followed a practically unchanging basic pattern wherein a succession of tanks contain various processing solutions and exposed sensitive sheets or strips must be successively transferred from one tank to another. It has been necessary in such systems to lead the film out of one solution in one tank and down into the succeeding tank. This increases the length of the film occupying each processing zone thus multiplying the total length of film subjected to processing action. It will appear hereinafter that this technique is wasteful and ineificient for a number of reasons.

In the present invention film is passed directly from one tank to another without emerging from the solutions which overcomes many disadvantages of prior systems and expands the capabilities of such systems.

One form of the apparatus is shown in FIGS. 1 and 2 wherein a single tank structure 10 is divided into a plurality of sections by dividing walls 11, 12, 13, 14 and 15. However separate tanks kept close together may be used. The structure shown will silmultaneously process a plurality of films or a single film. As shown the rolls 16 are received in the tank section 17. Film from each roll is fed through slots 18 in each common wall. The slots desirably are arranged in alignment lengthwise of the tank so that the film follows a linear path through the tank sections.

The tank section 19 may contain a developing solution, the section 20 may contain water, the section 21 may contain fixing solution while the section 22 may contain wash water. Various other solutions may be used and their sequence arranged for specific processing requirements. From the section 22 the film is passed through slots 18 in the wall 15 and into the section 23 where the processed film is wound upon take up spools 24 in a manner to be described. The tank sections 17 and 23 may contain water or may be dry.

The film supply rolls 16 containing exposed photosensitive material are rotatably received upon spindles 25 which are rigidly secured in base blocks 26 secured to the tank bottom. The take up spools 24 are also rotatively mounted upon spindles 27 fixed in base blocks 28. The spools 24 are provided with notched collars 29 at their upper ends which engage with driving members 30 which in turn are secured to vertical shafts 31 rotatable in bushings 32 secured to a cover member 33. The shafts 31 may be driven in any desired manner. However, they should all be operated at the same speed and by some suitable means having accurately controllable speed.

As shown in the drawings the shafts 31 extend thru and above the cover and have secured thereon worm gears 34 all of which mesh with worms 35 fixed to a shaft 36 rotatable in bearings 37 secured to the cover 33. The shaft may be driven by a hand crank not shown or more desirably by a motorized unit 38 which is accurately controllable at any desired speed to time the processing cycle. The spools 24 are provided with a slot 39 in which the leading end of each film is anchored. Other means for driving the take up spools may be employed.

The slots 18 are provided with means for sealing off the flow of solutions from section to section. One construction for such sealing means is shown in FIGS. 1, 2 and 4 wherein the opposing edges of the slots are faced with soft rubber squeegees having the form shown in FIG. 4, wherein the opposing rubber edges are flexible and will provide the required seal as the film 41 is drawn therebetween thus the liquid will not pass between sections while the film is in place nor will there be any substantial seepage when no film is present because the resiliency of the squeegees will close the slot.

In use the cover 33 is removed to insert the film strips. When so doing the driving clutches SI disengage from the spools 24 which permits empty 5130015 to be placed upon the spindle 25. To start the processing cycle the tank sections are filled with appropriate solutions and spools containing exposed film are placed upon the spindles in section 19. In a nonactinic environment the film is then threaded thru the slots 18 in each common wall and anchored in the take up spools after which the cover is replaced making sure the notched collars 19 are lined up with the lugs on the drivers 30. The motor is then adjusted to drive the film at the required processing speed and allowed to run until the cycle is completed.

When a plurality of different solutions are used the timing in the developing section should be accurately adjusted. This timing includes as a factor the length dimen sion of the developing tank section. The length of the other processing sections should be at least approximately in proportion to the required processing times at the succeeding processing tank sections.

Various sealing devices may be used in place of that shown in FIG. 4. For example, films may be fed between interengaging rubber rolls 42 which are arranged to constitute complete partitioning walls between tank sections. In this construction the rolls are sufiiciently resilient to permit the film to pass therebetween and serve to stop flow of solution between sections. A still further sealing means may take the form of a hollow resilient tube 43 cemented into the partitioning wall structure 44. The tube has oppositely disposed vertical slots therein for the passage of film. In this device if seepage of liquid occurs at the slots it may be drained off thru the open bottom end of the tube or it may be designed to provide for the passage of water therethru in which case the bottom of the tubes 43 are provided with tubes connected to a water supply while the top of the tube has a cap 45 provided with an outlet tube leading to a waste system. In this construction a body of fresh water is maintained between tank sections. The caps 45 are removable to permit insertion of film in slots 18.

More compact structures may be devised without departing from the invention wherein solution replenishing means and driving means including batteries may be combined with relatively small sized processing tank sections. Such a construction is shown partially diagrammatically in FIG. 3 where-in the tank unit 46 is divided into a relatively narrow processing section 47 and a fixing section 48 separated therefrom by a small Water bath section 49. End compartment 50 receives rolls 16 of exposed film and compartment 51 receives the finished film. Separating walls 52 may be of the construction shown in FIG. 5 or any other suitable construction.

The remaining space in the vessel 46 may be occupied by tanks of replenishing developer 53 and fixer 54. A driving unit 55 may also be enclosed in the unit. The output of this unit is coupled to the takeup spools in compartment 52 as shown diagrammatically at 56. Any suitable means may be used to supply water to the bath 49. Means may also be provided to replenish working solution in tank sections 47 and 48. Any means may be used for this purpose. A suitable automatic means may consist of regulating valves 57 communicating from the replenishing tanks 53 and 54 to the working tanks 47 4 and 48. The valves would be adjusted to maintain a constant level of solution in tanks 47 and 48.

The driving units 38 and 55 may desirably be provided with means to compensate for the gradual increase in diameter of the film wound upon the take up spools and thus insure uniform rate of travel of the film strip.

A valuable special use for the invention is that of providing accurate, rapid, reproducible, calibrated processing of exposed film strips. It should be noted that very short processing times are possible While maintaining accuracy and reproducibility. When required, processing times shorter than 5 seconds are possible.

In prior techniques using the dip in sequence the developing time is partially determined by the time the film is immersed in developer and partially by the time of travel from tank to tank. During the latter time however the film is exposed to air and rapid temperature change. The temperature change cannot be accurately determined and moreover indeterminate depletion of the developer strength during this period takes place as well as oxidation effects. These indeterminate factors makes accuracy impossible.

The linear development system of the invention evercomes the difficulties of prior practice since the length of the path traveled thru the developer is shown and does not change and the film enters the stop bath instantly after leaving the developing solution simply by passing thru the dividing wall.

Moreover since processing time is a function of film travel rate and solution path length it becomes apparent that the use of short path lengths is advantageous in that film travel rates may be slow thus conserving film use and solution volume may be small thus conserving solution. Minimum solution volume adds to the ease of cnanging test solutions when executing sensitometric operations.

Following the general structure of FIG. 3 a compact unit may be deviced for use upon the person of the user in which case the temperature of the solution in the processor would be maintained by the body temperature of the user. The miniaturized unit would contain a single cassette of exposed film such as 70 mm. sensitive material and a battery operated driving unit coupled to a take up roll to receive the finished film.

The film or other material would pass thru a narrow tank section along the side of the unit containing just enough monobath for a single roll of film. The entering and leaving slots for the film would be sealed by any of the sealing structures described above. With such an apparatus using a monobath which will develop a film under static conditions in 15 seconds the film will be developed at a rate of 14 inches per minute. A 15 foot roll of film can with the apparatus of the invention be developed in 13 minutes.

FIG. 6 illustrates diagrammatically a tank construction similar to that shown in FIG. 2 and having dividing walls arranged in the same manner. As shown the tank section at the left for holding the supply of unprocessed film is filled with water and the succeeding tank sections in order contain developer, water or stop bath, fixing solution and final wash water in the last two sections. It will be noted the level of developing solution is maintained higher than that of the liquid in the next two sections and the level of liquid in the final sections is lower than the level of the fixing solution.

In this arrangement the major portion of seepage between tank sections will flow from left to right which will best reduce contamination of solutions particularly of the critical developer solution. This controlled flow of seepage is due to the difference in hydrostatic pressure between tank sections. The difference in pressure at wall 14 reduces the tendency toward dilution of the fixing bath by the wash Water.

The structure of the invention lends itself to a further useful capability. Since the film is disposed in a vertical plane while moving thru the apparatus arrangements may be made for inspecting the film by transmitted light. This may be done by inserting transparent windows in opposite side walls of the solution containing tank sections. The film may then be illuminated on one side by light to which the film is insensitive but which is in the visible spectrum. The image may then be inspected by viewing it at the opposite window. Progress of development may be observed in this manner at the developing station and the finished film may be seen at the fixing station. The windows 58 are shown diagrammatically in dotted lines in FIG. 6 one pair being located at the developing station 59 and another pair of windows may be located at the fixing station 60. One window only of each pair is shown.

What is claimed is:

Photographic processing apparatus comprising at least one tank section containing processing solution, oppositely disposed narrow slots in the side wall of said tank section extending below the surface of the solution and References Cited by the Examiner UNITED STATES PATENTS 2,522,071 9/1950 Tait 134122 2,956,494 10/1960 Tyler 9589 X 3,067,758 12/1962 Hersh 13464 X 3,086,438 4/1963 Takats 9594 3,095,798 7/1963 Kelly 9594 3,122,086 2/1964 Fitch 95-94 NORTON ANSHER, Primary Examiner.

through which a film strip may enter and leave the tank 20 C B, PRICE, Assistant Examiner, 

